The Cytokinin-Activated Transcription Factor ARR2 Promotes Plant Immunity via TGA3/NPR1-Dependent Salicylic Acid Signaling in Arabidopsis
The Cytokinin-Activated Transcription Factor ARR2 Promotes Plant Immunity via TGA3/NPR1-Dependent Salicylic Acid Signaling in Arabidopsis
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DOI：
10.1016/j.devcel.2010.07.011
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发表时间：
2010-08-17
影响因子：
11.8
通讯作者：
Hwang, Ildoo
中科院分区：
文献类型：
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作者：
Choi, Jaemyung;Huh, Sung Un;Hwang, Ildoo
细胞分裂素影响植物对多种病原体的免疫力；然而，将植物源细胞分裂素与病原体反应相耦合的机制一直难以捉摸。在此，我们发现植物源细胞分裂素促进拟南芥对丁香假单胞菌番茄致病变种DC3000（Pst）的抗性。在细胞分裂素氧化酶（CKX）或异戊烯基转移酶（IPT）过表达植株或ahk2 ahk3突变体中，细胞分裂素水平或信号传导活性的调节与抗性改变相关。事实上，细胞分裂素激活的转录因子ARR2对Pst抗性有特定作用。水杨酸（SA）应答因子TGA3与ARR2结合，并且Pr1启动子中TGA结合顺式元件的突变消除了细胞分裂素和ARR2依赖的Pr1激活。在tga3植株中，细胞分裂素处理没有增加对病原体的抗性，因为细胞分裂素依赖的Pr1诱导被消除。此外，SA信号传导增强了ARR2/TGA3与Pr1启动子的结合。综上所述，这些结果表明细胞分裂素调节SA信号传导以增强对Pst的抗性，在这个过程中TGA3和ARR2之间的相互作用是重要的。
Cytokinins affect plant immunity to various pathogens; however, the mechanisms coupling plant-derived cytokinins to pathogen responses have been elusive. Here, we found that plant-derived cytokinins promote resistance of Arabidopsis to Pseudomonas syringae pv. tomato DC3000 (Pst). Modulated cytokinin levels or signaling activity in CKX- or IPT-overexpressing plants or in ahk2 ahk3 mutants correlated with altered resistance. In fact, the cytokinin-activated transcription factor ARR2 contributes specifically to Pst resistance. The salicylic acid (SA) response factor TGA3 binds ARR2, and mutation of TGA-binding cis-elements in the Pr1 promoter abolished cytokinin- and ARR2-dependent Pr1 activation. Cytokinin treatment did not increase pathogen resistance in tga3 plants, as the cytokinin-dependent induction of Pr1 was eliminated. Moreover, SA signaling enhanced binding of ARR2/TGA3 to the Pr1 promoter. Taken together, these results show that cytokinins modulate the SA signaling to augment resistance against Pst, a process in which the interaction between TGA3 and ARR2 is important.